1. Field of the Invention:
The present invention relates to novel emulsifiable linear polyethylene containing compositions which possess good color characteristics, such as high light transmittance, high density, and low penetration hardness values. The present invention also relates to a process for the production of such emulsifiable linear polyethylene compositions and the emulsions prepared from such emulsifiable linear polyethylene compositions.
2. Discussion of the Background:
Water emulsifiable polyethylene waxes are widely used as self-polishing waxes in commercial applications. These waxes are relatively easy to use, are inexpensive, and provide good results. The waxes, in addition to being used in self-polishing wax formulations for floor polish applications, are also useful in formulating textile finishes, paper coatings, and the like. However, for applications such as textile lubricants and fruit coatings, waxes characterized by having high densities and low penetration hardness values as well as good color characteristics are desired.
One method for producing emulsifiable polyethylene compositions involves a two-step procedure. The polyethylene is first thermally degraded and then oxidized. However, the presence of catalyst residues, such as Ti, Ca, Al, and Cl, results in a discoloration of the polyethylene during the thermal degradation step. Thus, emulsifiable polyethylenes produced by this process do not possess good color characteristics and are not suitable for use as textile lubricants and fruit coatings.
A process for oxidizing blends of specific polyethylene components and a specific microcrystalline wax is disclosed in U.S. Pat. No. 2,879,239. The products produced by the process are said to be especially valuable for the preparation of emulsions which, when spread on a surface, leave hard, tough films having a high gloss.
U.S. Pat. No. 4,632,955 discloses emulsifiable polyethylene paraffin blend compositions prepared by oxidizing a mixture of: (1) low density polyethylene (LDPE); (2) low density polyethylene wax; and (3) paraffin wax. By first blending the LDPE with paraffin wax, the initial viscosity of the polyethylene is lowered, and the thermal degradation step may be omitted. This method provides a savings in energy and a product with better color characteristics. However, the emulsifiable LDPE compositions possess low densities and high penetration hardness values and are, thus, unsuitable for use as textile lubricants or fruit coatings.
Thus, there is a need for emulsifiable polyethylene compositions which possess good color characteristics, high densities, and low penetration hardness values.